I have a laser graved, edge lit marquee.  I think it looks cool.  Tried to do 2 colors, but it didn't turn out as great as I wanted to because one of the colors, yellow, just wasn't bright enough.  The other color, red, looks great though.  
I applied tint to my screen plexi and to my marquee.  So when its off its completely black.  Looks neat.  I'll post a picture later.